A resonant motor may be controlled based on the load of the resonance motor. In order to accomplish such a control, the motor current or the peak amplitude of the moving motor armature of the resonant motor may be measured. This allows for the resonant motor to be controlled such that constant peak amplitude is always achieved independent of the load of the motor. Such a control is relatively complex and requires further elements in the control loop such as a position detector measuring the peak amplitude. In a situation where only a simple control is required, these solutions are relatively costly.
It is thus a desire to provide a resonant motor unit and a method of controlling a resonant motor in a relatively simple way.